References may be used to create complex data structures, pass multiple arrays and hashes to subroutines, and to create anonymous data structures
References are created by prefixing the name of a variable with a backslash
References are dereferenced by using the name of a reference (including the dollar sign) where we would usually use the alphanumeric name of a variable, or by using the arrow notation.
References can be included in Perl data structures anywhere you might ordinarily find scalars.
References to anonymous arrays may be created by initialising an array using square brackets instead of round ones.
References to anonymous hashes may be created by initialising an hash using curly brackets instead of round ones.